LINCOLN SQUARE — It's a fairly common habit among Chicagoans to group cans, bottles and paper products in plastic bags and toss the lot into the recycling bin.

Never mind that the plastic bag itself isn't recyclable.

After years of putting up with the practice, Streets & Sanitation is putting its foot down: Come Jan. 1, all recyclables must be placed loose in the city's blue carts.

Patty Wetli explains how to make sure your recycling gets recycled:

Recyclables contained in any bags (that means those paper Trader Joe's bags, too) will no longer be accepted, according to a Streets & San announcement made Monday.

"Everyone wants to do their part to help protect the environment, but when you put the wrong items in the blue cart — like a plastic bag — you contaminate not only your cart but a whole stream of otherwise useful materials," Streets & San commissioner Charles Williams said in a statement.

Plastic bags damage equipment at sorting facilities and also keep workers from seeing whether other non-recyclables — like pizza boxes or Styrofoam — have been placed in the cart. Streets & San incurs additional costs when non-recyclables have to be hauled from a sorting facility to a landfill, according to the announcement.

Because so many people remain confused about what can and can't be recycled, Streets & San is preparing to debut a new website — Recycle by City Chicago — that will clear up misconceptions and provide a better visual representation of how to recycle correctly.

The site will go live in December. Residents can sign up now for an email update.